Sound locator and computer for aircraft



Oct. 16, 1934. F. R. HOUSE SOUND LOCATOR AND COMPUTER FOR AIRCRAFT Filed Aug. 7, 1930 8 Sheets-Sheet 2 Oct. 16, 1934. F. R. HOUSE SOUND LOCATOR AND COMPUTER FOR AIRCRAFT Filed Aug. 7, 1930 8 Sheets-Sheet 5 0 a. W. m M, 0 mm ks a mm :QN m n u u x O A X o n iwx m o% n as Oct. 16, 1934.

F. HOUSE SOUND LOCA'IOR AND COMPUTER FOR AIRCRAFT Filed Aug. '7, 1930 8 Sheets-Sheet 4 .llllllllll/Ili! -i k' 79 M 4 INVENTOR fim/v/r 5/2 0085 ATT% RNEY Oct. 16, 1934. F, R. HOUSE SOUND LOCATOR AND COMPUTER FOR AIRCRAFT Filed Aug. 7, 1930 8 Sheets-Sheet 5 Oct. 16, 1934. F. R. HOUSE SOUND LOCATOR AND COMPUTER FOR AIRCRAFT 8 Sheet-Sheet a v INVENTQR fimN/r 5'. H0065 III'I'I 'I Filed Aug. 7, 1930 .I I I l I I l I l Il %TORNEY.

1934- F. R. HOUSE SOUND LOCATOR AND COMPUTER FOR AIRCRAFT Filed Aug. 7, 1 930 8 Sheets-Sheet 7 he? I W Oct. 16, 1934. F. R. HOUSE SOUND LOCA'IOR AND COMPUTER FOR AIRCRAFT 8 SheetsSheet 8 Filed Aug. '7, 1930 I l I I E, u w

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lovezalloo relates to for lccoemg and 5 oircl'eii; oi. niche so me cook eiz'ccef'l gun moy cc directed eheseou. Sec? emcee L oropcoe to use e sound locoeiog device such cc o lemme sound lcceizoc cool. to chercfirom co eeerc'ollghl time loco,- oz? emcee, either fill-eerily or through. as comgsez'etoe, esfcee applying cereein coxcectiene. gorooleoe of which this invention is o solution my be ceet emololmed by reference lo the ole memory oiogrcm in Fig. i. this figure the sound lccetoi' is shown ec L, the eeeiclullght et 5 end. the comotor ct G. The direction one ground speed oitlae airplane is indicated by vector P and the direction enolthe velocity of the wind is indicated by vector W; 11 the point Anew resents the eositicn of the airplane at the time the sound was tted, which is heard at L, then an 'lenewlllbeotpointfibytlietlmethe sound reaches the sound lccotor end is heard by the operator. angle a, therefore, represente whet be termed the sound leg le or cor-=- lecisioo. on account of the direction end velocity of the d, however, the operotor est L does not perceive the sound es ii it e from A, but se== ccivcs it as if il come from the point B, the d liovlng carried the sound cloves to e left due ins the time of tx'onsmiseion from A to L. The angle e, therefore, represents what may be *1. o. the wind error ox" wind correction eagle. If the seercblight, therefore, were located ct L, ll ehoulo he pointed clone the line M3 or SD, which is parallel to LB. It will be seen, however, that if the eeerchlight is poinled alone SD ac 'Wfll nee strike the target on account of the distance separating the seerchlight end sound locetoz. Therefore, there is another correction introduced, comely, the angle c which is moon es the perellex correction. It will he understood that all of these errors are shown in med 201m in the dlegrom and also the diagram ehows'uth errors only end in the simplest form where F and W and 1e are parallel. There me also similar errors in elevation but since such errors are relatively small and are based on line come princlple, me explanation regarding the some neeel not be repeated nor need all of them be taken into consideration in the preferred to of my epporotus.

Referring now to the detailed dreams in eeldicion to Fig. l,

Fig. 2 represents the some three elements, sound locetor, comperetor, end seerchlight, as shown in Fig. l on e. somewhat lei gez scale.

3 is 119, It, 11318 view showing one elc meme cocomcee loco lice corscciloo 01: com: cote? which lo oeeleeoelyolccecl lo the oece oi Elle eouoo lccoe I c is o oiclgeemmoclc view cl one oi the Eeyore cc" coseeclloo oxalic Fig.

c is tic view o2 we gee correcelco Fig. e ls o view of the elm cowecllcn I layer.

Fig. l is o'veceicei eecllco a a e-Motel of c ntrolllng o ugh the comp from the ziz A. C.

olet'cly cell the 88%? :92; in

Fig. 15 15 5e 213ml:

view of e. coo. C. and

D. C. p b-coco for m cm- The sound locelor is soc gen at L in Figs. 1 one] 2 end pref cc of a of he A and E m eport ln uth and.

euother of homo C and D spaced apart in elevation. There is one rotor for each pair of go home, l: uth operator lis w 1: through the eerpicces in the helmet E and the elevation operetor w. ugh the ear pieces in thehelmet F. All the home tum together but the azimuth coercion t them in math through handle G, and the elevotiozl operator similarly controls the horns in elevation through the handle H. The exect tions of the horns ln uth end elevalion ere not tttecl, however, but, the correcclone, heretofore exclaimed in connection with Fig. l, ere t introduced ugh the difierentlels 6 in m nth end 7 in elevotion, the computing h be low in the hose 13 of the sound locobor.

Refe now to 3 showing the computer etlc. developed form, the azimuth 1i Ii.

ice in clear shell 8 connected tome sound lccotor is shown as entering the. computer at the lower left hand corner of the end the shell: 2 connected to llle sound locotor io elevetion is shown es just above the shaft 8. The shaft 8 is shown as driving through suitable gearing so a gear 36 loose on the shaft 36 but which isnormeHy coupled to shaft 36 through a. gear 36' fixed to said shaft and a. pinion 71 which meshes normally" a"; the gear a with both gears 38 and 36" and is mounted on e, slideble shaft 64. Shaft 36 extends entirely through two sleeves, inner sleeve 37 and outer sleeve 38, and carries at its right hand end at poin' 'er 50, which shows, therefore, continuously the compass or azimuth angle of the sound locutoi'. Similarly the elevation angle is shown on dial on shaft 35 which is geared to shaft 2 through gee-ring T2. The sleeve 37 is shown as driven Zr "3.

carries at its righthend end i; dial 29, which shows the compass wind deviation angle 01 wind direction with respect to north, while the outer sleeve 38 is shown as driven from the gear 38 end casries through the 28 eonoen'mo ennulor dial 28 shows the som pass baseline deviation angle or the angle that the baseline LS makes with north. In connection with these aforesaid dials and pointers, there provided an outer fixed died 14 having compass mos-kings For the purpose of initially setting, and a ehronlzing the device I provide a. setting-mob so which is shown as having four: positions. when the mob is pushed to its extreme right position, which may be termed-the first position, the pinion so on the shaft 61 thereof is brought into mesh with the gear 38'. At the some time, due to the action of the pivoted clutch members 6263,the shaft 64 is moved in the reverse directi n throwing the pinion Soto the left out of mesh h gear 38,

when the parts are in this position the knob 48 is turned until the dial 28 on the upper sleeve is set for the baseline deviation angle. When the knob is in the position shown in the drawings, i. e.,

" 1 position 2, the parts are in their normal operating g. 3, seer 66 is engaged-with goes 3'? l is thrown out of mesh the seer caving, the pinion 71 in mesh with both and 365i and pinion 65 remaining in mesh gear so. In this position, thereiore, the

with

udjustment oi the knob 48 sets the middle sleeve or the dial 29 for the wind deviation angle. In the fourth or synchronizing position, gear 68 remains in mesh with gear 37' and the extra. gear 6'7 secured to the gear 67 is brought into mesh with the gear. 3'7, and gear '71 is disengaged from loose gear 36" with which meshes. If desired, an ind cator 49 may be operated from knob 48 showing which of the four positions. the knob is in (see Fig. 9). when knob 48 is turned, therefore, pointer may be turned to show the angle the sound locator makes to north.

I take 0*: from the several sleeves and shafts 38, 37 and 36 data for computing the wind correction, parallax correction and the sound lag correction. For this purpose there is shown nfimnted on the sleeve 38 (showing the baseline angle) a cam 43 which introduces a function of the angle of azimuth deviation, that is, though between the line 13 connecting the sound locator and Searchlight and the line connecting the sound locator and apparent target l 0 Fig. 1) Similarly the cam 45 is mounted on the sleeve 37 1'01 introducing a function of the angle between the wind and the target bearing line (1 4 Fig. 1).

' on, that is, is pushed one notch to the oveys-z sinx is tion by fonts w: A is put into the equation by com. salon the 35 which is shown as driven irom the shaft 8 through the train oi shown in dotted lines et Z2. The slant range is introduwd into the mechanism by the rod S" (Fig. 3 which is shown moving the slide 33 laterally irom the smut range mechenism in lever B. In Flgsfle and 5, however, the slant rouge is introduced by the rotation of the shaft S which turns the grooved eccentric vs, thereby moving the slide E3 laterally by the engagement of the pin '25 on the slide with the slot in the eccentric 74. The movement or the cam 43 moves up and down pin on rod 76 which pin takes in a'slide-way 71' which is positioned at an adjustable angle on her 78 (Figs. 5 and 8). The angle of the slide 77 is determined by an arm 79 carrying a roller 80 at its end, which in turn engages in a, horizontal slide-way 81 on the rod 82, which is moved from the cam e l. Slide '33 is, therefore, given e lateral movement dependent not only upon the position of the com to but else the position of the es (i. e. sin 6 end ens. n).

This movement of slide is tum i pei'ted to move up end down the cross bar This is accomplished by the pin secured to the slide 2e which engages in an singularly ad justable slide-way 84 pivoted on the cross bar 26, the angle being determined by the position of the bar 73 (B) through the engagement of roller 85 on an arm 86 secured to said slide-way 84. The output of the device, namely, the up and down movement of the bar 26v is taken out through the lever 87 (Fig. 3) where it is combined with the output of the wind correction layer output 27 and is transmitted to the final dial 20 showing the combined wind and parallax azimuth correction.

The wind correction layer is very similar in principle and solves the following equation Vain i KcocA wind,

to the u marked 5.

coroner the com 46. in this case the looting the vertica rods 7d" and ueted from time cams may be the some es before. Tee slant however, is not brought into this equation but instead the velocity of and are brought in through the setof dial 1? (Figs. 3 end 6) which moves rod ec rectilineerly through pimon 91 and rack teeth This positions the vertical slide-way to very the angular position of the slide-way 84 oily sinftobie leer '73 and thus the ber o down on amount p::oportion-= d devi tion angle. As shown 3, nowevei are three w ound wind role is introduced age wind equals 'iiloereiore i may use corn l? on sold sl'reit 35 putting in e, iiuiction of A and altitude is tire device by the oi time lznoo 12 on '51: which through reel; and pinion moves lie slide up and down (Figs. 3 and e).

A not spring co may be provided between the as end the bar 3% (Fig. l) so that the moon enisrn will not be damaged in case the maximum sleet range for which the apparatus is designed is exceeded. The up and down movement of the bar 34 turns the bell crank lever 93 about its pivot 99 on the pivoted arm ice. Said per 98 is also provided with o. track-way in which the roller on rod 9d engages. Therefore, it will be seen that the arm we is rocked about its pivot 101 on amount proportionel to the combined functions of the elevation engle (A) end altitude, i. e., slant range (R). 1.1 e output of this layer (it) imparted to the through the teeth are shown in is also imported to rotate spring r oleout its pivot zso the pu pose of entering into ti e computetion or the movement of the target druing the t me interval, is computed in layer 5 (Fig. 3). In however, tnetwo leyers 5 and e eresiiown super-imposed. This is accomplished by moons of a. smell gear sector we secured to the e we which meshes with another gear sector 1G3 secured to the spring arm 33. This leer spring, therefore, is positioned in. accordance with the slant range (R). Sold arm carries at each end rollers ice-roe which engage angular-1y adjustable track-ways 105-106. Said tregk-wgys are secured to shafts 106'106 which. give turned respectively from the azimuth sounding actuated flexible bellows 23 end the elevation sound leg actuated flexible bellows 22. The former is shown as actuated from T9. reversible suction or pressure pump 8' driven from the shaft 8' and, therefore, rotated in accordance with the rate of azimuth angular travel of the sound looator. The latter bellows 22 is similarly actuated from a pump 9, driven from the elevation shaft 2 through the large gear 90 and pinion 91, pump 9 being driven in proportion to the rate of angular elevation of the sound locator. For a fuller description of this particular portion of the apparatus, reference 15 had to applicants copending application No. 372,777, filed June 21, 1929 for Means for indicating rate and direction of movement. The pumps generate either posiportionel to the pumps speed, due to e constant leek in each pump. On the short 106 is secured the indicating dim 19 which is, therefore, the sound leg indicating azimuth dial (1. e., angular rate multiplied by time equals angular distance), and to the shaft ice" is secured the dial 1% which is, therefore, the sound lug indicator dial in eleretlon. With the spring 33 positioned in line the sheft lilo end roe", the bellows 22 and will obviously turn the clinic it and 3.; through linurn eagle because the rotation of the .u is unopposed by spring 35. in this po sltioo. tire dials will indicete the sound leg angle. As, however, the spring 33 is rotated about pivot 25o. on increasing force is opposed to tire expansion or the bellows end in that mennor the dlels indicate the rote in degrees per s ond, multiplied by the two in seconds, which is. of course, proportional to the slant range.

shown (Figs. 3 and 9) the indicators 2.9 endfio are placed side by side so that the markon 2o (pernllezr plus wind corrections) ere reed with respect to on index 19' on 19 so that the res-dings of the two dials are thus olgebrelceliy added. The final reading, therefore, gives the total correction for wind, parallax and sound leg. Slmilerlytiiere is mounted adjacent the dial it a second dial 21 for introducing the known error in elevation which is set in by means oi the knob 21' which mey put in the spotting correc tions.

The total azimuth error is then introduced into the system eutometicolly or by hand through the setting handle 10, the operetor rotating this mndle until the coerce end fine dials 31, 31' read the some as the reeg of 19-20. Through the difierentioi er, this totel correction is olgebrolcelly edded to the enimuth engle oi the sound locetor which is brought in through shaft 8 and the final corrected angle transmitted through the shaft 111 to transmitter 6. Similarly the oleration correction indicated on dials 1s and 21 are put in through handle ll so that the course and fine dials 32, 32 correspond to the readings of sold first mentioned dials. This correction is then algebraically added to the elevation angle through the difierential i2 and the final result transmitted to the transmitter 7. There may also be another slight correction in elevation due to the constructional mounting of the sound 10- cetor gears. and thismay be corrected for by dif= ferentlel 30, one side of which is driven from the shaft 2 and the other side from the shaft 8 through the gearing 112, the outputof the differential driving the sleeve 113 which drives one side of the difierential 42 through gearing 114.

The final output of the transmitters 6 and 'l is led as shown in Fig. 2 first'to what is known as a comparator from which the Searchlight is operated, and which compares or matches the train of the sound locator and Searchlight. The comparator is preferably located at a distance from the sound locator andsearchllght and has therein a repeater motor 114 actuated from the transmitter 6 and repeater motor 115 actuated from the transnntter 7 (see also Fig. 12). Each repeater motor operates an indicator 116--117 which shows respectively the position of the loll rec

vided for showing the azimuth and elevation of the searehlight so that the operators. by matching the indexes on the two pairs of indicators. may keep the searchlight pointed in the proper position to illuminate the target. To this end transmitter 121 and in turn controls the torque and direction of a power motor M. My preferred method of control is by shifting the relative position of the brushes 125 of the motor with respeettothe fleldpolesandthisisshownasaccomplished by turning a gear 126 irom the motor 145'. said gear forming one arm of the dinerential gear T. Tihe other arm comprises a gear 12'? whichis on the same hnh as the interest gear 3.28 and driven from shaft 129 of the mo tor hf. pinions l35-13l. The planetary arm of said geartrcin comprises the ironic F on which are mouriwd the brushes 125 and on which also mounted the inter-meshing pinione 139 and 13d one oil which meshes with the gear 127 and the other with the gear 125 and which also mesh with each other. The position of the brush therefore, is Jointly controlled by the repeater motor 145' and the power motor M so that the power motor causes the eearchlight to follow the movements of the repeater motor,

and relieves the repeater motor of all load. The power motor is shown as driving the searchlight through worm 131' on the shaft thereof driving the worm wheel 132 and pinion 133 which turns the large gear 134 on the base of the searchlight.

It will be understood that the searchlight is controlled in elevation by a similar mechanism through pinion 160 on the shaft motor M which a segmental gear 161 on the trunnion he searchlight (1'18. 2)

simplest form of the apparatus shown in 12 where direct current step-by-step meters are employed it is necessary to have some means ior synchronizing the apparatus and to end I have shown signal lights 140-140 at the sound locator and 141-141 at the computer. The first mentioned pair ofllghts are controlled respectively by switches 142-442 governed by cams 143 on the shafts of the repeater motors 114-115. These switches are designed to be closed by the cams when the indicators read zero so that the operators crank the transmitters around until the lights light and then by handles G and H they turn the sound locator to point north and horizontal. Similarly the comparator operators turn the cranks 1 -421 until the lamps 141-441 are lighted when it is known that the sound locatnr, comparator and searchlight are all pointing in the same direction and synchronized.

If desired a more or less self-synchronous system may be employed instead of the system shown in Fig. 12. Fig. 13 shows the use of alternating current Selsyn transmitters and motors, which system is partially self-synchronous. According to this system the Selsyn transmitter 6 in azimuth and 'l' in elevation actuate as heiore, the repeater motors 114 and and the transmittors 121' 12$ actuate the elevation and azi-= muth repeater motors 1425' 146. in the searchlight, the latter shifting the brushes of the power motors M-M' as before. In order to gain accuracy, however, in the Searchlight control the transmitters 121' and 122' are not connected "one to one" to the sending instrument but are-geared up thereto as indicated by the gearing 148-448 which, of courm, destroys self-wnchronism. Therefore it is desirable to have a synchronous repeat back system from the Searchlight to the comparator and this is provided by the coarse or one-to-one transmitters ice-15c on the searchlight which actuate the coarse repeater motors 151-151 at the comparator, which thus replace the answer-heck lights.

15 is identical in principle with Fig. 13 except that in place of using fine Selsyn trans mittens and motors irom the comparator to the searchlight I employ the step -hyqtep transmit hers 1:21 and i223 as in i2 and the step step repeater motors and M5. t iore, comhincs the eeli synehroncne i to which is used the sound comparator, an er-heclr from light to the companies with st why-s system need the control c painter to the Searchlight. This system 1,5,1. tain advantages since material torque is required to the brushes oi the motor for which the step-hy-step motors are better adantedthan Selsyn motors.

A completely self-synchronous system is shown. in Fig. 14. In this figure there is employed at the sound loeator coarse and fine azimuth transmitters 206-206' and coarse and fine elevation transmitters 207 and 207'. Since the system is completely self-synchronous the angles trans m tted may be led directly to the searchlight without going: through a comparator. Therefore, when the double-throw switch 160 is thrown to the left, in Fig. 14, the aforesaid coarse and fine transmitters are connected respectively to the coarse azimuth repeater motor 245 and coarse elevation-repeater motor 246 on the searchlight, while the fine transmitters 206' and 20'!" are connected respectively to the fine azimuth repeater motor 145' and fine elevation repeater motor 247 on the seanel'iliglit. In accordance with the systern disclosed in my prior Patent No. 1,862,017 for Distant control mechanisms dated June 7. 1232,'the sear'chlight is normally controlled from the fine motors M5 and 24? which turn the brushes of the power motors M as heretofore outlined. The azimuth coarse motor on the other hand is mounted on the base of the searchlight and the armature thereof carries a trolley 182 (Fig. 11) which normally contacts with the insulated segment 163 between two live segments 164165, the ring carrying said segments being stationary on shaft 211. Said live segments are in circuit with the reversible power motor 166 so that if the Searchlight should get out of synchronism with the sound locator to such an extent that the angle exceeds the angle subtended by the sector 163, the power motor 186 is brought into operation to overcome the Selsyn motor 145' and restore the Searchlight within the limits of synchronism oi the fine motor. The elevation control is identical through motor M, etc. The azimuth control is indicated in Fig. 11, it being understood that coarse motor 246 and its contacts are idle when the searchlight is employed in connection with the form of transmission shown. in the preceding figures.

As soon as the sesrchiight has been brought near the time a the soundlocatorit may be trolled from the auxiliary coarse and fine azimuth and elevation transmitters 170170'-171-,171, which it will be understood are turned by cranks 12o and121. 1 v

.As above stated the computer shown in Fig.8.

does-not attempt to compute wind error in elevation or parallax error in elevation, since these quantitiesare so small as to be negligible within 'the limits of error of the remai'nderof the apparatus. For very accurate work, however, it may be desirable to'includethese corrections. and in Fig. 10 I have shown diagrammatically how all corrections may be introduced automatically. In this figure, layers 8, 4, band 6 perform the same functions in the same manner as the corresponding layers in Fig. 8, namely, they introduce respectively the wind correction in azimuth.

parallax correction in azimuth, and sound lag correction in azimuth and in elevation and final- Lv comput the total errors in azimuth and elevation. In Fig. 10, however, I have two other layers, layer 1 which computes the wind correc tion .in elevation and layer 2 which computes the parallax correction in elevation. The latter is computed in accordance with the equation.

hwy-B coslvzsin A where the symbolslrepresent the same angles as before. This computation is effected in layer-12 correction is computed in layer 1 from-the cams as audio inaccordance withtheequation Vcosdoind I sirr'y' x where the symbols have-the samemeanmg as in the previous equations. The summation of the azimuth correction from layers-3 and 4 is transmittedtothedialZiiandthesummationofthe elevation correction from layers 1 and 2 is trans.- mltted to the dial- 21. layer 6 remains as before except that the dial 21 is set automatically from the elevation correction instead of through the Mob 21.

There is also shown in this figure a simplified methodof initially setting the cam shafts 36-37 and 38. In this instance the innermost shaft 38 is set by means of the dial 50', the inner sleeve 37 by the pointer 29' and the outer sleeve 38 by the pointer 28', all of which are locked in position by set screws (not shown) after being set. The remainder of the apparatus functions sub stantially as described in Fig. 3 and the description need not be repeated, the parts being given corresponding numbers throughout.

i There are, however, numerous sources of error in elevation which cannot be calculated, such as the wind refraction error and the temperature refraction error so that the errors in elevation, even if computed for wind drift and parallax, are usually larger than those in azimuth. For this reason I prefer not to attempt to compute the elevation errors except the sound lag error but to compute accurately the azimuth errors, thereby limiting the field of searth of the searchlight to a substantially vertical plane or line. It is 'tude of the-plane '(A).

found that an-aircraft can be pickedv up very quickly when the field of search is so limited.

. The operationof my device is as fo1lows: In setting upthe computer for operation the device is synchronized by bringing the sound locator and so searchlight to point north and horizontal while bringing all dials to. zero as explained above. Then.

the dials of the computer are set as follows:

(l) Dial 28 is set for the direction with respect to north of'the baseline LS between the sound 10- cator and searchlight. 4

(2) The dial 29 is set for the direction of the wind (o).

.(3) The dials l5 and 18 are set for the ground velocity of the wind and the elevation velocit of the wind respectively (V). a (4) The dial-12 is set for the estimated altl:

- The direction andvelocity of the wind are given by the meteorological stations and the altitude of the plane is estimated by taking into account the atmospheric ceiling. type f plane, and the angular. elevation when first heard. The .formula for determining the. corrections is such that errors in the making 01 0 estimation for valtitude are relatively unimportant, the most important factor in the correction being the angular velocity of the target.

The sound locator is then brought to bear upon the sounds coming from the target and is kept-m v on such target by the listeners at E and F.-. The angular velocity in azimuth and elevation is determined automatically from the rate at which the sound locator is moved in following the attacking aircraft. This rate, combined with the four settings mentioned above, automatically generates the necessary corrections, the total of which is automatically indicated and continuously applied to the angle which the sound locator transmits to. the comparator at the control station. The true position of the attacking aircraft .is thus designated at the comparator and the aearchlight is brought to bear upon the target. The errors are such that it is only necessary. for a searchlight operator" to. sweep through an area of every few degrees in elevation to pick up the. target, and this sweeping operation can be accomplished-within a few seconds. -As soon as the target is picked up the searchlight may, of course; be controlled directly from the handles 141 and 141' without reference to the sound locator position.

In accordance with the provisions of the patent statutes, I have herein described the principle and operation of my invention. together with the no apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of. these may be altered-and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I and desire to secure by Letters Patent is:

1. A system for locating aircraft at night comprising a sound locator, a Searchlight, means for 145 positioning the searchlight in accordance with the position of the sound locator. an automaticcorreetion device actuated primarily from said sound locator for continuously computing the sound lag error, and means for introducing said 150 correction into said searchlight podtioning means.

2. A system for locating aircraft at night comprisinga sound locator, a searchlight, means for sound lag error, the parallax error and the wind error, and means for introducing all of said corrections into said searohlisht positioning means.

3. A system for locating aircraft at night comprising a sound locator. a searchlight, means for computing the parallax error in azimuth, means for computing the wind in azimuth, means for computing thegound lag error in azimuth and in elevation, all of said means being primarily actuated from said sound locator, and means for continuously transmitting corrected sound locator azimuth and elevation angles including means for introducing the aforesaid computed errors.

4. Means for computing corrections for positioning searchlights from sound locator units including the combination with the sound locator and means for positioning the same in azimuth and elevation, computing mechanism actuated by the angular movements of the sound locator for computing the sound lag error in both azimuth and elevation, means for computing the azimuth parallax correction to compensate for the spacing of the sound locator and searchlight, means for computing the slant range from the altitude of the target and a function of the angle of elevation of the sound locator, and

means for introducing said slant range as a measure of time in both the azimuth and elevation sound lag mechanisms to give the component sound lag errors and as a function in the azimuth parallax correction means.

5. Means for computing corrections for positioning searchlights from sound locator units includingthe combination with the sound locator and means for positioning the same in azimuth and elevation, means actuated by the angular movements of the sound locator for generating the angular rates of movement thereof in azimuth and elevation, means actuated by the azimuth position of the sound locator for computing the parallax correction to compensate for the spacing of the sound locator and searchlight, means for. computing the slant range from the altitude of the target and a function of the angle of elevation of the sound locator, and means for introducing said slant range as a measure of time in both the azimuth and elevation rate mechanisms to give the component sound lag errors and as a function in the azimuth parallax correction means.

6. Means for computing corrections for positioning searchlights from sound locator imits including the combination with the sound locator and means for positioning the same in azimuth and elevation, computing mechanism actuated by the angular movements of the sound locator for computing the sound lag error in both azimuth and elevation, means for computing the azimuth parallax correction to compensate for the spacing of the sound locator and searchlight, means for computing the slant range from the altitude of the target and a function of the angle of elevation of the sound locator, and means for introducing said slant range as a measure of time in at least the azimuth sound lag mechanisms to give the component sound lag errors and as a function in the azimuth parallax correction means.

'1. Means for computing corrections for positioning searchlights from sound locator units including the combination with the sound locator and means for positioning the same in azimuth and elevation, means actuated by the angular movements of the sound locator for generating the angular rates of movement thereof in azi-' muth, means actuated by the uth position of the sound locator for compu ing the parallax correction to compensate for the spacing of the sound locator and searchlight, means for computing the slant range from the altitude of the target and a function of the angle of elevation of the sound locator, and means for introducing said slant range as a measure of time in the azimuth rate mechanism to give the component sound lag error and as a function in the azimuth parallax correction means whereby the field of search is limited to a line instead of a three dimensional search.

8. In a sound locator, means for computing the angular correction for sound lag comprising means for computing the slant range, means for generating the angular rate of movement of the sound locator in azimuth and in elevation, and means of combining a function of said range and the azimuth and elevation rate to give the angular correction in azimuth and elevation.

9. In an aircraft sound locator movable in azimuth and elevation, means for computing the angular corrections for sound lag comprising meansv for combining the elevation angle and altitude of the craft for slant range, means for generating the angular rate of movement of the sound locator in azimuth and elevation, and means for combining a function of said range with each of said rates to give both components of the angular correction.

10. In a system for flashing a searchlight on aircraft at night, the combination with a sound locator and remotely positioned searchlight and means for turning each in azimuth and elevation, angle transmitting means actuated by the tuming of the sound locator to direct the searchlight, and correction mechanism for correcting the transmitted angles including means positionable in accordance with a function of the angle between the sound locator and the baseline between the searchlight and sound locator, means positionable in accordance with a function of the angle between the wind and said base, means positionable in accordance with a function of the elevation angle of said sound locator, means positionable in accordance with the altitude, a plurality of mechanical means actuated thereby for computing the sound lag angle at least in azimuth, the parallax angle and the wind correction angle, and means for introducing said correction into the transmitted angles.

FRANK R. HOUSE. 

